Defensive publication

ABSTRACT

THE COVERING POWER OF DEVELOPED SILVER OF PHOTOGRAPHIC GELATINO SILVER HALIDE COATINGS IS INCREASED BY THE ADDITION OF INORGANIC AMMONIUM SALT COVERING POWER AGENTS SUCH AS AMMONIUM SULFATE OR AMMONIUM NITRATE. THESE AGENTS MAY BE COMBINED WITH A POLYACRYLAMIDE TO PROVIDE EVEN GREATER INCREASES IN COVERING POWER. FOR EXAMPLE, A FINE GRAINED CHLOROBROMIDE EMULSION CONTAINING 60 G./MOLE AG OF (NH4)2SO4 IS COATED ON A CELLULOSE ACETATE SUPPORT AT 168 MG./FT.2 AG AND 600 MG./FT.2 GELATIN. UPON EXPOSURE AND DEVELOPMENT IT IS FOUND THAT THE INCORPORATION OF THE AMMONIUM SULFATE IN THE EMULSION MARKEDLY INCREASES THE MAXIMUM DENSITY AND THE COVERING POWER OF THE DEVELOPED SILVER, AS COMPARED WITH EMULSIONS CONTAINING POLYMERIC COVERING POWER AGENTS.

DEFENSWE PUBHCATTQN UNITED STATES PATENT OFFICE Published at the requestof the applicant or owner in accordance with the Notice of Dec. 16,1969, 869 O.G. 687. The abstracts oi! Defensive Publication applicationsare identified by distinctly numbered series and are arrangedchronologically. The heading of each abstract indicates the number ofpages of specification. including claims and sheets of drawingscontained in the application as originally filed. The files of theseapplications are available to the public for inspection and reproductionmay be purchased for 30 cents a sheet.

Defensive Publication applications have not been examined as to themerits of alleged invention. The Patent Ofllce makes 10 assertion as tothe novelty of the disclosed subject matter.

PUBLISHED JULY 20, 1971 T888 005 PHOTOGRAPHIC SILVEIR HALIDE EMULSIONSHAVING INCREASED COVERING POWER Glen M. Dappen and Thomas E. Whiteley,both of 1669 Lake Ave, Rochester, NY. 14615 Filed Sept. 4, 1970, Ser.No. 69,978 Int. Cl. G03c 1/02 US. Cl. 96-94 No Drawing. 17 PagesSpecification The covering power of developed silver of photographicgelatino silver halide coatings is increased by the addition ofinorganic ammonium salt covering power agents such as ammonium sulfateor ammonium nitrate. These agents may be combined with a polyacrylamideto provide even greater increases in covering power. For example, a finegrained chlorobromide emulsion containing 60' g./mole Ag of (NHQ SQ; iscoated on a cellulose acetate support at 168 mg./f. Ag and 600 mug/ft.gelatin. Upon exposure and development it is found that theincorporation of the ammonium sulfate in the emulsion markedly increasesthe maximum density and the covering power of the developed silver, ascompared with emulsions containing polymeric covering power agents.

